Process of melting and deoxidizing metals and alloys



Patented May 3, 1932 PATENT ounce 'WILHELM'. REITMEISTER, OF KIRCHMOSER(HAVEL) wERKyGEnMANY PROCESS OI IELTING AND DEOXIDIZING META I-SANDALLOYS 1N0 brewing. Application filed Kay 10, 1929, Serial No. 362,142,and in Germany June 16, 1928.

lln order to cast metals, for example copper alloys, gunmetal or thelike, a melting process is commonly used, in which old metal and newmetal are melted together in oil or like ti ltnrnaces without crucibles.It has long been lrnown that during this process copper alloysespecially take up oxygen thus forming oxides of the metals whichdissolve in the molten bath. These oxides are, however, allll readypresent in higher or lower percentages in the ingredient materials.struction of these harmful oxide-compounds has been attempted by meansof phosphorus, manganese alloys, aluminium and a whole l series citother metallic deoxidizing agents. These, however, are only partiallyeffective.

lrnown that carbon has the greatest deoxidicing action on molten ironand steel containing oxygen. The present invention is based on thesefacts and consists in a process :lor melting and deoxidizing metals andmetal alloys, in particular copper alloys, and including iron and ironalloys, in which oxy- M gen compounds and carbon are added to themelting ath, in such proportions that the oirygen content of the oxygencompounds hears exactly or substantially the correct ratio to thecarbon-to produce carbon monoxide This is effected by mixing first ofall onygen carriers such as UuO or Zn() or MnO or ll eU "with coal-dustin such proportion that the oxygen content of the oxide carrier relativeto the carbon content is in proportion to the combining weights for theformat-ion of llll A certain excess of coal is necessary according tothe metallic oxide andthe alloy employed owing to the unavoidable lossesarising when introducing the mixture into the molten metal bath. It hasnevertheless been proved that no carbonization talzes place inconnection with iron alloys.

The lollowing reactions take place for example:

Ox de dissolved n lll'ature of melting Solid deox1- alloy bath dizmgagent Result hopper alloy CuO C110 C) =2Cu C0 11 0 C110 C) =3Cu C0,llron alloy FeO FeO C) =2Fe CO,

W The principle of the process is to remove Hitherto the dethe oxygen ofthe bath in the form of CO gas which is insoluble in most melting baths.

The addition of the mixture of oxides and coal-dust to the melting bathin such relative proportion as to produce the unsaturated compound CO isan essential feature. In thisway any harmful excess of oxide or of coalis avoided. According to the metals in the bath only such substances arechosen. as oxide carriers of which the reduction products produce noharmful effects when they come into contact with the molten metal. Forexample CuO should not be used for steel, nor iron oxide for copper,since Cu is harmful to steel andiron to copper.

A part of the detrimental properties espe cially of copper and copperalloys and also of other non-iron metals is due to material withdissolved carbon monoxide. If the deoxidizing agent according to thepresent invention is added to such material which cannot be determinedeither by a chemical or metallographic investigation the metal willbecome worse because more CO gas is formed in the melting bath. By meansof amelt to which one of the deoxidizing agents is added it can V bedetermined after the cooling whether the present metal was oxidiferousor metal with dissolved carbon monoxide.

With the presence of excessive carbon (disand in what manner the same isto be performed, I declare that what I claim is A process for meltingand deoxidizing metals and metal alloys selected from a group comprisiniron, copper alloys, and iron alloys, whic process consists in addingoxyen compounds and carbon to the melting ath, in such proportions thatthe oxygen content of the oxygen compounds bears substantially thecorrect ratio to the carbon to produce carbon monoxide gas. I Intestimony whereof I aflix my signature.

W'ILHELM REITMEISTER.

